Stacey Emmonds

Anthropometric and physical characteristics of english academy rugby league players.

Abstract Till, K, Tester, E, Jones, B, Emmonds, S, Fahey, J, and Cooke, C. Anthropometric and physical characteristics of English academy rugby league players. J Strength Cond Res 28(2): 319–327, 2014—The purpose of the present study was to evaluate the anthropometric and physical characteristics of English academy rugby league players by annual-age category (under 16s–under 20s) and between backs and forwards. Data were collected on 133 academy players over a 6-year period (resulting in a total of 257 assessments). Player assessments comprised of anthropometric (height, body mass, sum of 4 skinfolds) and physical (vertical jump, 10- and 20-m sprint, estimated V[Combining Dot Above]O2max via the yo-yo intermittent recovery test level 1, absolute 1 repetition maximum [1RM], and relative squat, bench press, and prone row) measures. Univariate analysis of variance demonstrated significant (p ⩽ 0.05) increases in height, body mass, vertical jump, absolute, and relative strength measures across the 5 annual-age categories (e.g., body mass: under 16s = 75.2 ± 11.1, under 20s = 88.9 ± 8.5 kg; vertical jump: under 16s = 45.7 ± 5.2, under 20s = 52.8 ± 5.4 cm; 1RM bench press: under 16s = 73.9 ± 13.2, under 20s = 114.3 ± 15.3 kg). Independent t-tests identified significant (p ⩽ 0.05) differences between backs and forwards for anthropometric (e.g., under 16s body mass: backs = 68.4 ± 8.6, forwards = 80.9 ± 9.7 kg) and physical (e.g., under 19s 20-m sprint: backs = 3.04 ± 0.08, forwards = 3.14 ± 0.12s; under 18s relative squat: backs = 1.65 ± 0.18, forwards = 1.51 ± 0.17 kg·kg−1) characteristics that were dependent on the age category and measure assessed. Findings highlight that anthropometric and physical characteristics develop across annual-age categories and between backs and forwards in academy rugby league players. These findings provide comparative data for such populations and support the need to monitor player development in junior rugby league players.

Longitudinal development of anthropometric and physical characteristics within academy rugby league players

Abstract Till, K, Jones, B, Darrall-Jones, J, Emmonds, S, and Cooke, C. Longitudinal development of anthropometric and physical characteristics within academy rugby league players. J Strength Cond Res 29(6): 1713–1722, 2015—The purpose of this study was to evaluate the annual and long-term (i.e., 4 years) development of anthropometric and physical characteristics in academy (16–20 years) rugby league players. Players were assessed at the start of preseason over a 6-year period and were required to be assessed on consecutive years to be included in the study (Under 16–17, n = 35; Under 17–18, n = 44; Under 18–19, n = 35; Under 19–20, n = 16). A subset of 15 players were assessed for long-term changes over 4 years (Under 16–19). Anthropometric (height, body mass, sum of 4 skinfolds) and physical (10- and 20-m sprint, 10-m momentum, vertical jump, yo-yo intermittent recovery test level 1, 1 repetition maximum [1RM] squat, bench press, and prone row) assessments were collected. Paired t-tests and repeated measures analysis of variance demonstrated significant annual (e.g., body mass, U16 = 76.4 ± 8.4, U17 = 81.3 ± 8.3 kg; p < 0.001, d = 0.59) and long-term (e.g., vertical jump, Under 16 = 44.1 ± 3.8, Under 19 = 52.1 ± 5.3 cm; p < 0.001, d = 1.74) changes in anthropometric and physical characteristics. Greater percentage changes were identified between the Under 16–17 age categories compared with the other ages (e.g., 1RM squat, U16–17 = 22.5 ± 19.5 vs. U18–19 = 4.8 ± 6.4%). Findings demonstrate the annual and long-term development of anthropometric and physical characteristics in academy rugby league players establishing greater changes occur at younger ages upon the commencement of a structured training program within an academy. Coaches should understand the long-term development of physical characteristics and use longitudinal methods for monitoring and evaluating player performance and development.

Seasonal changes in anthropometric and physical characteristics within English academy rugby league players.

Abstract Till, K, Jones, B, Emmonds, S, Tester, E, Fahey, J, and Cooke, C. Seasonal changes in anthropometric and physical characteristics within English academy rugby league players. J Strength Cond Res 28(9): 2689–2696, 2014—Professional rugby league clubs implement training programmes for the development of anthropometric and physical characteristics within an academy programme. However, research that examines seasonal changes in these characteristics is limited. The purpose of the study was to evaluate the seasonal changes in anthropometric and physical characteristics of academy rugby league players by age category (i.e., under 14, 16, 18, 20). Data were collected on 75 players pre- and postseason over a 6-year period (resulting in a total of 195 assessments). Anthropometric (body mass, sum of 4 skinfolds) and physical (10- and 20-m sprint, vertical jump, Yo-Yo intermittent recovery test and 1 repetition maximum squat, bench press, and prone row) measures were collected. The under 14s and 16s showed greater seasonal improvements in body mass (e.g., under 14s = 7.4 ± 4.3% vs. under 20s = 1.2 ± 3.3%) and vertical jump performance than under 18s and under 20s. In contrast, under 18s and under 20s players showed greater seasonal improvements in Yo-Yo performance and 10-m sprint (e.g., under 14s = 1.3 ± 3.9% vs. under 20s = −1.9 ± 1.2%) in comparison to under 14s and under 16s. Seasonal strength improvements were greater for the under 18s compared with under 20s. This study provides comparative data for seasonal changes in anthropometric and physical characteristics within rugby league players aged 13–20 years. Coaches should be aware that seasonal improvements in speed may not exist within younger age categories, until changes in body mass stabilize and consider monitoring changes in other characteristics (e.g., momentum). Large interplayer variability suggests that player development should be considered on an individual and longitudinal basis.

Anthropometric, speed and endurance characteristics of English academy soccer players : Do they influence obtaining a professional contract at 18 years of age?

This study evaluated the anthropometric, speed and endurance characteristics of English academy soccer players, comparing players who obtained a ‘professional’ contract at 18 years old with those that did not (‘academy’); 443 male academy soccer players from an English professional club undertook anthropometric (height and body mass), speed (10 and 20 m sprint) and endurance (Yo-Yo intermittent endurance test level 2 [Yo-Yo]) assessments between 2005 and 2012. Significant improvements with age were found for speed and endurance at each annual age group up until U18 age category. Significant differences were only observed between ‘professional’ and ‘academy’ players for 10 m (p = 0.003, η2 = 0.01) and 20 m (p = 0.001, η2 = 0.01) speed at U16 and U18 and Yo-Yo performance (p = 0.001, η2 = 0.12) at U18 age category. Practitioners should use speed and endurance assessments for monitoring physical development of players rather than for talent identification purposes.

Physical Qualities of International Female Rugby League Players by Playing Position

Abstract Jones, B, Emmonds, S, Hind, K, Nicholson, G, Rutherford, Z, and Till, K. Physical qualities of International Female Rugby League players by playing position and injury history. J Strength Cond Res 30(5): 1333–1340, 2016—The purpose of this study was to investigate the anthropometric, body composition, and fitness characteristics of female rugby league players by playing position. Data were collected on 27 players who were part of the English elite womens rugby league squad. Player assessments comprised anthropometric (stature and body mass), body composition (dual-energy X-ray absorptiometry) and fitness {lower-body power (countermovement jump [CMJ], 20 kg jump squat [JS], and 30 cm drop jump), 5, 10, 20, 30, and 40 m sprint, 505 agility, Yo-Yo intermittent recovery test level 1} measures. Players were classified into playing position (i.e., forwards and backs) before analysis. A multivariate analysis of variance demonstrated significant (p ⩽ 0.05) differences for body mass, stature, total fat, lean mass, and percentage body fat between forwards and backs. Positional differences were also observed for speed, agility, and lower-body power. Significant relationships were observed between total body fat and all fitness variables, and total lean mass was related to CMJ and JS peak power. This study provides comparative data for female rugby league forwards and backs. Body fat was strongly associated with performance and should therefore be considered in developing fitness characteristics. The relationship to match performance and trainability of these characteristics warrants further investigation.

Seasonal changes in physical qualities of elite youth soccer players according to maturity status: comparisons with aged matched controls

ABSTRACT Purpose: Longitudinal studies assessing the seasonal development of strength, speed and power qualities are limited in youth soccer players. The purpose of this study was to evaluate the seasonal changes in the physical development of elite youth soccer players across Pre-, Circa- and Post-Peak Height Velocity (PHV), against a similar age and maturity matched control groups. Methods: One-hundred and twelve male elite youth soccer players (Pre-PHV n = 55; Circa-PHV n = 21; Post-PHV n = 36) and 38 controls consisting of non-elite active participants (Pre-PHV n = 18; Circa-PHV n = 10; Post-PHV n = 10) all undertook isometric mid-thigh pull strength, 10–30 m sprints, change of direction speed (CODs) and countermovement jump (CMJ) tests pre- and post-season. Results: The elite Circa-PHV improved greater than the control group for all physical qualities between pre- and post-season. The elite Pre-PHV improved greater in sprints, CODs, CMJ jump height and strength while the elite Post-PHV group improved more in CODs and strength than their respective control groups. Conclusion: Findings suggest that systematic academy soccer training enhances the development of physical qualities in youth soccer players but maturity status may impact upon such adaptations.

Accessing off-field brains in sport; an applied research model to develop practice.

Applied researchers (eg, academic researchers, PhD students) strive to undertake research that can inform practice in sport, and evidence ‘ impact.’ Conversely, practitioners (eg, coaches, physiotherapists, clinicians, sports scientists) strive to apply relevant up-to-date research findings to develop or optimise practice, adopting ‘ evidence based practice. ’ Despite the researcher and practitioner within a discipline having similar overall aims (eg, improve athletic performance, reduce injury risk, optimise return to play practices), their primary roles appear different due to various contextual factors.1 2 Researchers are able to work slowly, dedicating time to solving complex problems, whereas practitioners working in the field are required to work fast, to provide day-to-day support to coaches and athletes.1 The differences in how the researcher and practitioner work can be problematic and challenge the alignment of their respective priorities within their roles (eg, timescales required to deliver outcomes, specific expertise and experience, resources). Here we share a model demonstrating how the ‘working fast1 on-field brain3’, ‘working slow1 off-field brain3’ and ‘research-practitioner2’ can work together to undertake and integrate research into practice and solve the above problems. The alignment of (applied) research questions, expectations and usability of outcomes into practice …

Hydration strategies of professional elite rugby league referees during super league matches

Due to the focus of research within athletic populations, little is known about the hydration strategies of rugby league referees. We observed all eight full-time professional referees, during 31 Super League matches to investigate the drinking strategies and magnitude of dehydration (body mass loss) experienced by referees during match play. Referees arrived and remained euhydrated (urine osmolality; pre and post-match 558 ± 310 and 466 ± 283 mOsmol·kg−1). Mean body mass change was −0.7 ± 0.8%, fluid loss was 890 ± 435 g and fluid intake was 444 ± 167, 438 ± 190, 254 ± 108 and 471 ± 221 g during pre-match, first half, half-time and second half. This study suggests that elite referees adopt appropriate hydration strategies during match-play to prevent large reductions in body mass, although individual variability was observed. Future research should investigate dehydration in referees from other sports and the effects on refereeing performance.

The influence of age and maturity status on the maximum and explosive strength characteristics of elite youth female soccer players

ABSTRACT Purpose: Research has characterised the strength characteristics of elite youth male soccer players, although little is known about female players. This study investigated the influence of age and maturity status on strength characteristics of elite youth female soccer players. Methods: 157 female soccer players (U16; n = 46, U14; n = 43, U12; n = 38, U10; n = 30), recruited from three elite female soccer academies. Linear mixed models were used to determine the difference by age or maturation on maximum and explosive strength characteristics. Results: Peak force (PF) was possibly and likely greater for older age groups; however, differences in relative PF were most likely trivial between consecutive age groups. Relative impulse at 100 and 300 ms was very likely greater at U12 than U10, likely and possibly less at U12 than U14 and most likely less and possibly greater at U16 than U14. Relative PF was likely less at pre-peak height velocity (PHV) than circa and circa than post-PHV. Relative impulse at 100 and 300 ms was most likely lower for pre-PHV than circa and pre-PHV than post-PHV, and possible greater at circa than post-PHV. Conclusion: Age and maturation impact upon PF and impulse; thus, practitioners should account for individual maturation status when comparing players. These data provide reference strength data for elite youth female soccer players, which can be used when monitoring player development.

Influence of age on the anthropometric and performance characteristics of high-level youth female soccer players:

The purpose of this study was to evaluate the anthropometric and performance characteristics of high-level youth female soccer players by annual-age category (Under 10 (U10)–U16). Data were collected from 157 female soccer players (U16, n = 46; U14, n = 43; U12, n = 38; U10, n = 30), recruited from three high-level female soccer academies in England. Players completed assessments of anthropometry (height and body mass), isometric mid-thigh pull strength, jump height, aerobic capacity, change of direction (505-left/right) and speed (10 and 30 m). Magnitude based-inferences were used to assess for practical significance between consecutive age groups. Height (very likely–most likely), body mass (very likely–most likely), absolute strength (most likely), jump height (likely–very likely) and distance on the YYIRL1 (possibly–most likely) were greater in older players. Both speed and change of direction time were most likely to very likely lower in older players. However, only most likely trivial–possibly trivial differences were observed in relative strength between age groups. Findings suggest that physical characteristics except for relative strength differentiate by age categories. These findings provide comparative data and target reference data for such populations and can be used by coaches and practitioners for player development purposes. Practitioners should be aware that relative strength does not differ between age categories in high-level youth female soccer players.